Commorientes Rule UK: Simultaneous Death, Section 184 LPA 1925 and Survivorship Clauses

Updated 27 May 2026 · 8 min read · Wills & Estate Planning

If two people die at the same time — in a car accident, plane crash, or other common calamity — the order in which they died can determine who inherits what. English law resolves the uncertainty through the commorientes rule in section 184 of the Law of Property Act 1925, which presumes the older person died first. Without a survivorship clause in your will, this presumption can produce unexpected and tax-inefficient results.

What Is the Commorientes Rule?

Commorientes (from the Latin for “dying together”) refers to a group of people who die in the same incident or in circumstances where the sequence of deaths cannot be established. Before 1925, English common law had no clear rule: courts applied various presumptions depending on the facts, producing inconsistent outcomes.

The Law of Property Act 1925 settled the position. Section 184 creates a clear default rule: where the order of death is uncertain, the deaths are presumed to have occurred in order of seniority — the older person is presumed to have died first, and the younger last.

How Section 184 Works in Practice

Suppose Alice (aged 72) and Bob (aged 68) die in a car accident and the order of their deaths cannot be established. Under section 184:

Alice (older) is presumed to have died first.
Bob is presumed to have survived Alice, even momentarily, and therefore inherited her estate.
Bob’s estate then distributes Alice’s inherited assets — along with his own estate — under his will or on intestacy.

The consequence is that Alice’s assets flow through Bob’s estate before reaching the final beneficiaries. This can produce a double inheritance tax charge (once in Alice’s estate, again in Bob’s) and means the ultimate destination of Alice’s property is determined by Bob’s will rather than her own.

Why Survivorship Clauses Matter

A survivorship clause (or survivorship condition) in a will requires a beneficiary to survive the testator by a fixed period — commonly 28 or 30 days — before they are entitled to inherit. If the beneficiary dies within that period, the gift passes to the named substitute beneficiaries as though the primary beneficiary had predeceased.

For spouses and civil partners, a 28-day survivorship clause prevents assets from briefly passing through the surviving spouse’s estate in a simultaneous-death scenario. This avoids:

A double inheritance tax charge as the same assets are taxed twice in quick succession
The assets ending up with the surviving spouse’s beneficiaries rather than those intended by the first testator
The administrative burden of two separate estates both dealing with the same assets

A 28-day clause must be drafted carefully for spouses: if both die within 28 days, the spouse exemption from IHT in the first estate may be lost. Specialist will drafters sometimes include an express provision preserving the IHT exemption for the survivorship period to avoid this trap.

Application to Joint Tenancy

Joint tenancy property passes by the right of survivorship: the surviving joint tenant inherits the deceased’s share automatically. Where both joint tenants die simultaneously, section 184 determines which of them is deemed to have been the “survivor.” The younger joint tenant is presumed to have survived the older, so the property passes through the younger person’s estate.

For couples who want more control over the ultimate destination of their jointly held property, severing the joint tenancy to become tenants in common — so each person’s half-share passes under their own will — may be preferable to relying on the commorientes presumption.

Rebutting the Presumption

Section 184 is a default rule, not an irrebuttable presumption. If there is evidence — forensic, medical, or from witnesses — that the order of deaths can be established, that evidence prevails and section 184 does not apply. The courts will accept reliable evidence of the order of deaths and distribute the estates accordingly.

In practice, establishing the order of death in a simultaneous accident is genuinely difficult. Forensic pathology can sometimes assist, but in a catastrophic incident the evidence may simply not exist. The section 184 presumption then operates as the legislative solution to an otherwise irresolvable problem.

FAQs

What is the commorientes rule and when does it apply?

Commorientes (Latin: 'dying together') is the legal doctrine that determines the order of death — and therefore the destination of inheritance — when two or more people die at the same time or in circumstances where the sequence of deaths cannot be established. In English law the primary rule is found in section 184 of the Law of Property Act 1925: where two or more persons have died in circumstances making it uncertain which survived the other, the deaths shall be presumed to have occurred in order of seniority — the older person is treated as having died first. The rule applies whenever the order of death genuinely cannot be established from available evidence; it does not apply if there is any reliable evidence — forensic, medical, witness — that allows the order to be determined.

What does section 184 of the Law of Property Act 1925 say?

Section 184 of the Law of Property Act 1925 provides: 'In all cases where, after the commencement of this Act, two or more persons have died in circumstances rendering it uncertain which of them survived the other or others, such deaths shall (subject to any order of the court), for all purposes affecting title to property, be presumed to have occurred in order of seniority, and accordingly the younger shall be deemed to have survived the elder.' The effect is that the older person's estate is distributed first (on the assumption they died first), and then the younger person is treated as having inherited and subsequently died, so their estate distributes that property too. This can create a double tax charge and unexpected distribution chains — which is why survivorship clauses are so widely recommended.

How does the commorientes rule affect survivorship clauses in a will?

A survivorship clause (also called a survivorship condition) in a will requires a beneficiary to survive the testator by a specified period — typically 28 or 30 days — in order to inherit. Where the testator and the primary beneficiary (e.g. spouse or partner) die in a common calamity, the survivorship clause prevents the gift from passing briefly through the beneficiary's estate before being distributed again. Without such a clause, the section 184 presumption would apply: the older person's estate would pass to the younger (who is presumed to have survived), then immediately pass out of the younger person's estate — potentially to different beneficiaries and with a double inheritance tax charge. A 28-day survivorship clause avoids this and is standard in almost all professionally drafted wills.

Does the commorientes rule apply to joint tenancy?

Yes, but with a specific statutory modification. Under section 184, if two joint tenants die simultaneously, the older is presumed to have died first, meaning the younger is treated as having survived — and therefore as having become the sole owner of the jointly held property by survivorship before their own death. The property then passes through the younger person's estate under their will or on intestacy. However, in practice, many simultaneous-death situations are resolved by express terms in the parties' wills (survivorship clauses) or by survivorship period provisions that avoid the mechanical operation of section 184. Where joint tenants are married or civil partners, the inheritance tax spouse exemption may apply to the first estate but not to property that the younger spouse is deemed to have inherited and re-passed, compounding the tax exposure.

How can I protect my estate against the commorientes rule?

The most effective protection is a well-drafted survivorship clause in your will. A 28-day survivorship condition on all gifts to your primary beneficiary means that if they die within 28 days of you — whether in a shared accident or otherwise — the gift does not pass through their estate; instead it falls to the substitute beneficiaries named in your will. Most wills include this clause as a matter of course. For spouses or civil partners, a 28-day clause must be used carefully: if both spouses die within 28 days, the spouse exemption from inheritance tax may be lost on the first estate (because the surviving spouse did not survive for 28 days). Solicitors sometimes use a 30-day clause with a specific carve-out preserving the IHT spouse exemption for the first 30 days. If you hold joint tenancy property, consider whether severing the tenancy to tenants in common gives better control over where your share ultimately ends up.

What happens if the order of deaths can actually be established?

Section 184 only applies when the order of deaths is genuinely uncertain. If there is evidence — forensic pathology, witness accounts, medical records, or other reliable information — that establishes which person died first, that evidence prevails and section 184 has no application. The court will apply the established order of death, and property will pass accordingly. If there is a dispute about the evidence, the court can make a declaration on the order of deaths under the court's inherent jurisdiction or under the Administration of Justice Act 1985. The section 184 presumption is rebuttable by sufficient evidence; it is a default rule, not an irrebuttable presumption of law.

Include a Survivorship Clause in Your Will

WillSafe’s DIY will kit for England and Wales includes a standard 28-day survivorship clause and substitute beneficiary provisions — protecting your estate from the commorientes trap.

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